1. Field of Invention
The present invention relates to an LED lighting module. More particularly, the present invention relates to an LED lighting module equipped with two kinds of LEDs with different thicknesses and emitting different wavelength lights.
2. Description of Related Art
Since the light emitting diodes are equipped with advantages of small size, low power consumption and long lifetime etc., they have been gradually applied in a variety of lighting products, such as car headlights, street lights, traffic lights, general lighting, and even applied in a special landscape lighting and display backlight modules.
Traditionally, a mature manufacturing method of white light emitting diode is based upon a blue light-emitting diode with a yellow phosphor to produce white light, e.g., using the yellow-yttrium aluminum garnet (YAG) phosphor with blue LED chip to produce white light. However, since the luminous efficiency of the YAG phosphor powder decreases with increasing temperature, the generated white light has poor color rendering due to lacking the red light spectrum. Another white LED manufacturing method is based upon a blue LED chip with green phosphors and red phosphors to produce green and red light so as to generate a hybrid white of mixing the remaining blue light with green and red light. This LED manufacturing method is to have red and green phosphors mixed together in encapsulant materials, thereby causing the red phosphors to absorb not only the blue lights but also absorb the green lights generated by green phosphors and convert into red lights (also referred as “light absorbance interference”. Therefore, the latter LED manufacturing method reduces the amount of green lights, thereby affecting the quality of the final white lights.
For the forgoing reasons, there is a need for a better LED structure or mechanism to overcome the shortcomings in the prior art.